Drop for electric circuits.



I battery B to the;frame'3 of-the drop WILLIAM H. ROBINS,- oF MINNEAPOLIS, MINNES A, AssreNoRf TOAL/IERL- 'lcAN BANK PROTECTION co oFMINNEAPoLrs, MI NESOTA.

A To" (LZZ whom zltxrnwy concern.

Be it kIiOWn,tl1at 1, WILLIAM H. RoBINs, .of Minneapolis, Hennepin county, Minnesota,

h'av'e invented certain .new and useful Improvements' inDrops for Electric Circuits, of,

. of the guides 21 and a stop '26. When, therewhich the following is a specification; My invention relates to signaling drops used in connection with electric circuits, and particularly'tothose circuits used in' burglar- I 10 alarm systems; and the object of my inven tion is. to, rovide means whereby when the local circuit is closed the drop will surely operate to close the primary or alarm circuit.

' A further object is toprovide means for breaking the circuit quickly whenthe drop is released, and'thereby prevent arcing atthe contact-points.

The invention consists generally invarious" constructions and combinations, all "as hereinafter described and particularly Point? .ed out in the claims.

In the accompanying drawings, forming "part of this spec fication, Figure lis a detail- View of the drop in its normalposition with I Fig. 2

the primary circuit broken or open.

- is a similar View showing the drop released to close the primary circuit. 3 is-a view illustrating the drop connected with the alarm-gong. Fig. 4 is a detail view showing the construction of the drop.

In the drawings, 2 represents a suitable base, whereon the'metallic frame 8. of the drop is secured. 4 represents the magnets of the drop, 5 the armature having a hook 6 at end adapted to project through 'a'slot 7- ina' drop-plate 8,

ries. a weight 10 to insure the Which'is pivoted at 9 on said frame and caruick positive fall of the plate when released. A contact 11 is provided in the path ,of the plate 8, mounted on a block .12 of-- insulating material and connected. by a wire 13 t0 one side of the electric gong 14. Theothe'r side of the gong is connected by the wire 15 with a wire 1ng. A sliding 16, which leads from the frame 17 throu h a h magnets 4 are connected by a wire 18 with the lining 19 of avault, (not shown,) the numerals .17 and 19 in Fig. 3 representing sec tions, respectively, of the vault frame and lin- Specification 6f Letters Patent. Application iiledDecember B, l905i Serial No. 290.570.

p n 20 is mounted inguides. :21 on abl'ock 22 of insulating-materiahand a DROP FOR-ELECTRIQ omou'lrs.

Patented April 9, 1907.

I contact-post 23 in said block is connected by in circuitwith the pin 20, and said pin is'vnorrnally held in contact with the plate 8 bya spring 25,- arranged onsaid pin betweenone fore, contact is made between the frame and lining and the circuit is closed through the a wire 24 with the magnets, and said post is.

magnets 4, thearmature 5 will be attracted to release the pivoted plate .8. As the cur rent passes through the inQZO and theplate 8' the circuit will not be roken immediately upon the release of said plate, but will remain'closed' and fholdthe armature a ainst the magnets until the late8 and the s iding pin are separated. T 's separation will not gagcd the contiguous guide. The tension of the spring 25 will .be exerted to press the pin 20 forward into contact with the plate 8, and

take place until the pin has moved to the limit of its travel :and the button. 26 has en- 3 hold it in such contact with a yielding'pres-H-- sure and insure the immediate movementxof the plate as soon as the armature is actuated and prevent arcing between the V plate, which frequently results W en the plate drops by gravity alone, and as the circuit is'not broken until the plate has been hook on the armature it follows that if the circuit through the magnets is once closed thermore, the yielding pressure of the pin 20 on the drop-plate will overcome any friction or, sticking between the 'armatureook and the plate. and positively actuate the said plate as soon as it isreleased to close the alarm-circuit; As soon asth'e plate Shae engaged the contact 11 a new circuit will be established through the frame of the drop and the plate 8 to the contact 1-1 and from thence through the wire 13 to .thegong.

To insure-a good connection between the plate 8 and the frame of. the drop, I prefer to provide a wire 27, connecting sald plate with itspivot-pin, which is mounted in said frame.-

the magnets will remain closed a sufficient length of time to insure the disengagement of With this apparatus" the local circuit throughthe drop'epla'te frcm'the armature. and therein and moved out of its point of engagement with the l and close the circuit throughthe gong. Fur- IOO by the operationof the dropwill be made more certain and the efficiency of the device -ma,terially increased.

I claim as my invention ,.1. The combination with a-norinally open.-

alarm-circuit, of anormally openlocal circult, a circuit-closer in said local circuit having a drop arranged when relased to close said cuit, a circuit-closer in said circuit having a drop arranged when releasedto close said alarm-circuit, a slidilig-pin'in said local circuit, guides for 'said'pin, a spring-coiled on said in and arranged to hold-the same in yielding contact Withsaid" drop, and a stop for limiting the'fnovement of said pin, sub

' .Wit said drop andmeans permitting a limited movement of said pin when said drop is restantially as described.

- 3. The combination, with anormally open alarm-circuit, of a normally open local cir-.

, cuit, a'circuitcloser in-said local circuit having. a drop arranged when released to close sa d alarm-circuit, guides 2 1 provided on said circuit-closer, "a pin 20 slidabIy" mounted in said guides and having a stop 26 and a spring coiled on said pin betweensaid stop and one of said guides, and said pin normally bearing with a'yielding pressure on said drop and having a limitedtravel therewithwhen said drop is released, substantially as described.

stant'ially as described 4. The combination, with a normally open alarm-circuit, of a normally open local circuit, a circuit-closer comprising electromagnets, a drop-plate and an armature arranged yielding pressure, and said pin being-in said ocal circuit, whereby the circuit will conhavinga drop arranged, when releasedto,

close'said alarm-circuit, an insulating-block, a sliding pin mounted in guides on said block and connected W-ithjsaid local'circuit, means for ieldingly holding said pin in engagement leased, whereby the said pin will follow said drop for a predetermined distance, and-the circuit between them will be unbroken, sub

In wltness whereof I have hereunto set my hand this2 2d da-y of November, 1905.

' r a WILLIAM H. ROBINS.-

Witnesses: I

RIoHAR'n PAUL, C, MACNAMARA.

'tinue unbroken for a predetermined period- 

